Substrate processing apparatus having a middle electrode

ABSTRACT

A substrate processing apparatus may include a vacuum chamber, a substrate supporting unit disposed at lower portion of an inside of the vacuum chamber, and an electric field forming unit forming an electric field inside the vacuum chamber. The electric field forming unit may include an upper electrode disposed at an upper portion of the inside of the vacuum chamber, a lower electrode disposed in the substrate supporting unit, and a middle electrode disposed between the upper electrode and the lower electrode.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority under 35 U.S.C. § 119(a) to KoreanPatent Application No. 10-2021-0007395 filed on Jan. 19, 2021, which isincorporated herein by reference in its entirety.

BACKGROUND 1. Technical Field

Embodiments of the disclosure provide a substrate processing apparatushaving a middle electrode and a method of processing a substrate usingthe substrate processing apparatus.

2. Related Art

Recently, as semiconductor devices have been minimized and highlymultilayered, the difficulty of processing a substrate (e.g., asemiconductor wafer) with etching processes is increasing. In order toform a pattern having a high aspect ratio, a metallic hard mask havingexcellent etching selectivity is used, but it is difficult to withstandetching damage even with a metallic hard mask.

SUMMARY

A substrate processing apparatus in accordance with an embodiment of thedisclosure may include a vacuum chamber, a substrate supporting unitdisposed at lower portion of an inside of the vacuum chamber, and anelectric field forming unit forming an electric field inside the vacuumchamber. The electric field forming unit may include an upper electrodedisposed at an upper portion of the inside of the vacuum chamber, alower electrode disposed in the substrate supporting unit, and a middleelectrode disposed between the upper electrode and the lower electrode.

A substrate processing apparatus in accordance with an embodiment of thedisclosure may include a vacuum chamber, a gas supplying unit configuredto supply gases into the vacuum chamber, a supporting plate disposed ata lower portion of an inside of the vacuum chamber, an upper electrodedisposed at an upper portion of the inside of the vacuum chamber, alower electrode disposed in the supporting plate, and a middle electrodeadjacent to an upper surface of the supporting plate. The middleelectrode may include an end portion configured to physically contact anedge region of a wafer on the supporting plate.

A method of processing a substrate in accordance with an embodiment ofthe disclosure may include loading a wafer onto a supporting plate of asubstrate supporting unit in a vacuum chamber, evacuating the vacuumchamber using a gas exhausting unit, supplying one of a reactive gas, aprecursor, or a plasma into the vacuum chamber using a gas supplyingunit, and processing the wafer using an electric field forming unit.Using the electric field forming unit may include forming an electricfield. Forming an electric field may include applying an upper electrodevoltage to an upper electrode, applying a lower electrode voltage to alower electrode, and applying a middle electrode voltage to a middleelectrode. The middle electrode is physically in contact with the wafer.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic structural diagram of a substrate processingapparatus according to an embodiment of the disclosure.

FIGS. 2A to 2D, and 3A and 3B are views illustrating a middle electrodein contact with an upper surface of a wafer.

FIGS. 4A to 4C are views illustrating a wafer processed using thesubstrate processing apparatus according to an embodiment of thedisclosure.

DETAILED DESCRIPTION

Embodiments of the disclosure provide a substrate processing apparatushaving a middle electrode and a method of processing a substrate usingthe substrate processing apparatus.

Embodiments of the disclosure provide a method and a process forapplying a voltage to a metallic hardmask of a wafer in processing asubstrate.

FIG. 1 is a schematic structural diagram of a substrate processingapparatus 100 according to an embodiment of the disclosure. Referring toFIG. 1, a substrate processing apparatus 100 according to an embodimentmay include a vacuum chamber 10, a gas supplying unit 20, a substratesupporting unit 30, a gas exhausting unit 40, and electric field formingunits 51 to 54.

The gas supplying unit 20 may supply, from outside of the vacuum chamber10, various reactive gases, precursors, or plasmas into the vacuumchamber 10. The reactive gases may include at least one of a gas for anetching process, a gas for a depositing process, a gas for a purgingprocess, and a gas for a cleaning process. The gas supplying unit 20 mayinclude a gas supplying pipe 21, a mass flow meter 22, a gas deliverypipe 23, and a gas distribution unit 24. The gas supplying pipe 21 maysupply gases to the mass flow meter 22 from a gas tank or a gasreservoir. Although only one gas supply pipe 21 is shown in the drawing,the gas supply pipe 21 may include a plurality of sub-gas supply pipes(not illustrated). The mass flow meter 22 may control a flow rate ofvarious gases as the gases are transferred into the vacuum chamber 10.Although only one mass flow meter 22 is shown in the drawing, the massflow meter 22 may include a plurality of sub-mass flow meters (notillustrated). The gas delivery pipe 23 may deliver the reactive gases,the precursors, or the plasmas from the mass flow meter 22 to the gasdistribution unit 24 disposed in the vacuum chamber 10. The gas deliverypipe 23 may deliver and supply the reactive gases, the precursors, orthe plasmas into the vacuum chamber 10 through an upper portion and/or aside portion of the vacuum chamber 10. The gas distribution unit 24 mayuniformly distribute the reactive gases, the precursors, or the plasmasinto the vacuum chamber 10. In an embodiment, the gas distribution unit24 may include a shower head. For example, the gas distribution unit 24may include a plurality of gas injection openings 24 a. In anembodiment, the gas distribution unit 24 may include a baffle plate.

The substrate supporting unit 30 may be disposed at a lower portion ofinside of the vacuum chamber 10. The substrate supporting unit 30 mayinclude a supporting plate 31 and an actuator 32. A substrate (e.g., awafer) W may be loaded on the supporting plate 31. In an embodiment, thesupporting plate 31 may include an electro-static chuck (ESC). In anembodiment, the supporting plate 31 may include a vacuum chuck. Theactuator 32 may perform a rising operation, a descending operation, anda rotating operation. Accordingly, the supporting plate 31 can beraised, lowered, and rotated by the operations of the actuator 32.

The gas exhausting unit 40 may include a gas exhausting pipe 41 and avacuum pump 42. The gas exhausting pipe 41 may transmit the reactivegases, the precursors, and the plasmas from the inside of the vacuumchamber 10 to the vacuum pump 42. The vacuum pump 42 may exhaust thereaction gases, the precursors, and the plasmas from the inside of thevacuum chamber 10 to outside of the vacuum chamber 10. The vacuum pump42 may evacuate gases inside of the vacuum chamber 10.

The substrate processing apparatus 100 may further include coils 61disposed outside the vacuum chamber 10. The coils 61 may form a magneticfield inside of the vacuum chamber 10. The coils 61 may be disposed on asidewall of the vacuum chamber 10. In an embodiment, the coils 61 may bedisposed above the vacuum chamber 10.

The electric field forming units 51 to 54 may include an upper electrode51, a lower electrode 52, a middle electrode 53, and a controller 54.The upper electrode 51 may be disposed at an upper portion of inside ofthe vacuum chamber 10. The upper electrode 51 may be disposed above thegas distribution unit 24 of the gas supplying unit 20. The lowerelectrode 52 may be embedded or disposed in the supporting plate 31. Inan embodiment, the lower electrode 52 may be disposed below thesupporting plate 31. The upper electrode 51 and the lower electrode 52may form a plasma P in the vacuum chamber 10 and may form an electricfield to allow reaction of the plasma P with the wafer W.

The middle electrode 53 may be disposed adjacent to the supporting plate31 of the substrate supporting unit 30. In an embodiment, the middleelectrode 53 may be disposed adjacent to an upper surface of thesupporting plate 31. In an embodiment, the middle electrode 53 may bedisposed adjacent to a side surface of the supporting plate 31. Thesubstrate supporting unit 30 may further include an edge ring 33disposed on an edge portion of the supporting plate 31. The edge ring 33may be mounted on the supporting plate 31, and may be configured to becoupled to and separated from the supporting plate 31. The edge ring 33may include an insulating material such as quartz. In an embodiment, themiddle electrode 53 may be disposed adjacent to the edge ring 33disposed on the supporting plate 31. In an embodiment, the middleelectrode 53 may penetrate the edge ring 33 of the supporting plate 31.In an embodiment, the middle electrode 53 may be embedded in the edgering 33. The middle electrode 53 may be in contact with the wafer W. Themiddle electrode 53 may be electrically in contact with a conductivematerial layer disposed on an uppermost portion of the wafer W. Forexample, the middle electrode 53 may be directly in contact with theconductive material layer of the wafer W or may be capacitivelyconnected with the conductive material layer of the wafer W. Byinserting a dielectric between the middle electrode 53 and theconductive material layer of the wafer W, an electrical connectionbetween the middle electrode 53 and the wafer W may be substantiallyformed. In an embodiment, the substrate processing apparatus 100 mayinclude at least two middle electrodes 53 disposed along a periphery ofthe supporting plate 31 of the substrate supporting unit 30.Accordingly, the middle electrodes 53 and the wafer W may have two ormore contact points.

The controller 54 may apply a voltage to the upper electrode 51, thelower electrode 52, and the middle electrode 53. The controller 54 mayperiodically change the voltage. For example, the controller 54 mayadjust the voltage to the upper electrode 51, the lower electrode 52,and the middle electrode 53 so that applied voltage levels vary,independently.

FIGS. 2A to 2D, and 3A and 3B are views illustrating a middle electrode53 in contact with an upper surface of a wafer W. The wafer W mayinclude a lower layer 71, a middle layer 72, and an upper layer 73. Thelower layer 71 may include an etch target layer. For example, the lowerlayer 71 may include one of a silicon substrate, a silicon oxide layer,a silicon nitride layer, or other non-conductive material layer. Themiddle layer 72 may include a conductive material layer. For example,the middle layer 72 may include a metallic etch mask layer. The upperlayer 73 may include a non-conductive material layer. For example, theupper layer 73 may include a photoresist pattern. The middle electrode53 may be physically or electrically in contact with the middle layer 72of the wafer W. For example, the middle electrode 53 may penetrate theupper layer 73 of the wafer W to be in contact with an edge region ofthe middle layer 72. Because the middle layer 72 may be entirely formedon the lower layer 71 of the wafer W, the middle layer 72 may beparallel to the lower electrode 52 in the supporting plate 31.Accordingly, the middle layer 72 and the lower electrode 52 may formelectrodes of a capacitor. The middle electrode 53 may have a stick-likeor rod-like shape. An end of the middle electrode 53 may taper into apoint and may have a needle-like shape. A needle-shaped end portion ofthe middle electrode 53 may be rounded or may end in a substantiallyflat surface.

Referring to FIG. 2B, the middle electrode 53 may include a body portionB and an end portion E. The end portion E may directly contact the waferW. The body portion B may have a vertical pillar shape. Thecross-section of the body portion B may have different shapes indifferent embodiments. For example, the body portion B may have verticalside surfaces that are substantially flat. The end portion E may have aninverted cone shape, an inverted pyramid shape, or an inverted wedgeshape. The end portion E may have a pointed shape and may physicallypenetrate the upper layer 73. For example, the distal or furthest end ofthe end portion E may have a needle shape or a pinnacle shape. In anembodiment, the distal or furthest point of the end portion E may berounded. The body portion B and the end portion E of the middleelectrode 53 may include a conductor such as metal.

Referring to FIG. 2C, the end portion E of the middle electrode 53 mayinclude a pointed end tip E2 and an end body E1 that may have aninclined side surface. The end tip E2 may include an insulating materialsuch as Teflon or a plastic. The end tip E2 may be formed from amaterial that is harder than the material used to form upper layer 73 ofthe wafer W, which may facilitate the physical penetration of the upperlayer 73 of the wafer W.

Referring to FIG. 2D, the wafer W may include an exposed edge area EA,and the middle electrode 53 may be directly in contact with the middlelayer 72 that is exposed in the edge area EA. In the edge area EA of thewafer W, a part of the upper layer 73 may be removed to expose themiddle layer 72. The end portion of the middle electrode 53 may differin various embodiments with or without exposed edge area EA. Forexample, referring to FIG. 2B, the middle electrode 53 may include theend portion E. Referring to FIG. 2C, the middle electrode 53 may includethe end body E1 and the end tip E2. The end portion of the middleelectrode 53 may be rounded or flat. Thus, the inventive conceptsdescribed with reference to FIGS. 2B to 2D may be compatible with eachother and with embodiments with or without an exposed edge area EA.

Referring to FIGS. 3A and 3B, the middle electrode 53 may include a bodyportion B and an end portion E. The body portion B may have elasticity.For example, the body portion B may have a flat spring or a stick shapehaving elastic properties. The end portion E of the middle electrode 53may have a bent shape. For example, the end portion E of the middleelectrode 53 may have an elbow shape or a bracket shape. The end portionE of the middle electrode 53 may also have elasticity. In an embodiment,the body portion B of the middle electrode 53 may have a horizontal baror horizontal stick shape disposed to extend horizontally. In anembodiment, the middle electrode 53 may have an inclined shape. Forexample, the middle electrode 53 may form an angle in a range of 0° to90° with respect to a top surface of the middle layer 72 of the wafer W.

Referring to FIG. 3A, the end portion E may have a curved or bent shapewith a vertex protruding downwardly. At the lowest end or the point ofthe vertex, the end portion E may descend and rise to be rounded or tohave a V-shape so that the end portion E of the middle electrode 53 andthe middle layer 72 of the wafer W may be in contact with each other.

Referring to FIG. 3B, the end portion E may have a sliding bar shape ora segment shape inclined with respect to the body portion B. Forexample, the end portion E may form an angle in a range of 0° to 90°with respect to the body portion B. The middle electrode 53 or the waferW may translate in a horizontal direction so that the end portion E andthe middle layer 72 of the wafer W may be in contact with each other.The end portion E of the middle electrode 53 may slide onto an edge ofthe middle layer 72 of the wafer W. In other embodiments, the middleelectrode 53 or the wafer W may translate in the vertical direction sothat the end portion E of the middle electrode 53 and the middle layer72 of the wafer W are in contact with each other.

FIGS. 4A to 4C are views illustrating a wafer W processed using thesubstrate processing apparatus 100 according to an embodiment of thedisclosure. For example, a process of selectively etching the wafer Wusing reactors R will be described.

Referring to FIGS. 1 and 4A, a method of etching the wafer W using thesubstrate processing apparatus 100 may include loading the wafer W onthe supporting plate 31 of the substrate supporting unit 30 in thevacuum chamber 10, creating a vacuum inside of the vacuum chamber 10using the gas exhausting unit 40, supplying at least one of the reactiongas, the precursors, or plasmas into the vacuum chamber 10 using the gassupply unit 20, and processing the wafer W using the electric fieldforming units 51 to 54.

Processing the wafer W using the electric field forming units 51 to 54may include applying a first upper electrode voltage Va1 to the upperelectrode 51, applying a first lower electrode voltage Vb1 to the lowerelectrode 52, and applying a first middle electrode voltage Vc1 to themiddle electrode 53 to perform the substrate processing process in afirst period. The first upper electrode voltage Va1 may be a groundvoltage or a negative (−) voltage, the first lower electrode voltage Vb1may be a positive (+) voltage, and the first middle electrode voltageVc1 may be a positive voltage or a floating voltage. The floatingvoltage may be a state in which no voltage is applied to the middleelectrode 53. Due to the electric field that develops between the upperelectrode 51 and the lower electrode 52, the reactors R are stronglysubjected to the electric field and move relatively quickly , from aperiphery of the upper electrode 51 to the surface of the wafer W, andin the subsequent reactions, the lower layer 71, the middle layer 72,and the upper layer 73 of the wafer W may be etched. In this case, theupper layer 73 of the wafer W may selectively expose a part of the lowerlayer 71 and a part of the middle layer 72. The middle layer 72 of thewafer W may selectively expose a part of the lower layer 71.Accordingly, the reactors R may partially remove the lower layer 71 andthe middle layer 72 of the exposed wafer W. The lower layer 71 may beetched more easily than the middle layer 72 due to an etchingselectivity. In an embodiment, the first upper electrode voltage Va1 andthe first lower electrode voltage Vb1 may be interchanged. For example,the same voltage as the first lower electrode voltage Vb1 may be appliedto the upper electrode 51, and the same voltage as the first upperelectrode voltage Va1 may be applied to the lower electrode 52. In anembodiment, the first middle electrode voltage Vc1 may be a middlevoltage that falls between the first upper electrode voltage Va1 and thefirst lower electrode voltage Vb1. In an embodiment, the middle layer 72may be completely covered with the upper layer 73 and might not beetched. For example, the exposed lower layer 71 and the upper layer 73may be partially removed.

Referring to FIGS. 1 and 4B, a method of processing the wafer W usingthe substrate processing apparatus 100 may include applying a secondupper electrode voltage Va2 to the upper electrode 51, applying a secondlower electrode voltage Vb2 to the lower electrode 52, and applying asecond middle electrode voltage Vc2 to the middle electrode 53 toperform the substrate processing process in a second period. The secondupper electrode voltage Va2 may be a ground voltage or a negative (−)voltage, the second lower electrode voltage Vb2 may be a higher positive(+) voltage, and the second middle electrode voltage Vc2 may be apositive (+) voltage lower than Vb2 or a ground voltage. For example,the second middle electrode voltage Vc2 may be a middle voltage thatfalls between the second upper electrode voltage Va2 and the secondlower electrode voltage Vb2. Because the second middle electrode voltageVc2 is applied to the middle layer 72 of the wafer W, an electric fieldbetween the upper electrode 51 and the lower electrode 52 can beadjusted. For example, the physical energy of the reactors R bombardingthe middle layer 72 of the wafer W may be controlled. Therefore, damageto the middle layer 72 can be alleviated or reduced.

Referring to FIGS. 1 and 4C, a method of processing the wafer W usingthe substrate processing apparatus 100 may include applying a thirdupper electrode voltage Va3 to the upper electrode 51, applying a thirdlower electrode voltage Vb3 to the lower electrode 52, and applying athird middle electrode voltage Vc3 to the middle electrode 53 to performthe substrate processing process in a third period. The third upperelectrode voltage Va3 may be a ground voltage or a negative (−) voltage,the third lower electrode voltage Vb3 may be a positive (+) voltage, andthe third middle electrode voltage Vc3 may be a negative (−) voltage.For example, the third middle electrode voltage Vc3 may be a voltagehaving the same polarity as the third upper electrode voltage Va3. Themiddle electrode voltages Vc1-Vc3 may be changed or varied between theupper electrode voltages Va1-Va3 and the lower electrode voltagesVb1-Vb3.

Because the third middle electrode voltage Vc3 is applied to the middlelayer 72 of the wafer W, the bombardment of reactors R with the middlelayer 72 of the wafer W may be mitigated, or the physical energydirected to the middle layer 72 of the wafer W may be significantlyreduced or weakened.

When processing the wafer W using the substrate processing apparatus100, damage to a metallic material layer (e.g., the middle layer 72)formed on the wafer W may be alleviated. Accordingly, even if the middlelayer 72 is thin, etching processes can be performed in a stable manner,so that fine pattern etching processes and high aspect ratio etchingprocesses can be improved.

According to embodiments of the disclosure, the severity of damage tothe metallic hardmask on the wafer can be reduced so that a patternhaving a high aspect ratio can be stably formed.

While this disclosure contains many specifics, these should not beconstrued as limitations on the scope of the present teachings or ofwhat may be claimed, but rather as descriptions of features that may bespecific to particular embodiments of the present teachings. Certainfeatures that are described in this patent document in the context ofseparate embodiments can also be implemented in combination in a singleembodiment. Conversely, various features that are described in thecontext of a single embodiment can also be implemented in multipleembodiments separately or in any suitable sub-combination. Moreover,although features may be described above as acting in certaincombinations and even initially claimed as such, one or more featuresfrom a claimed combination can in some cases be excised from thecombination, and the claimed combination may be directed to asub-combination or variation of a sub-combination.

Similarly, while operations are depicted in the drawings in a particularorder, this should not be understood as requiring that such operationsbe performed in the particular order shown or in sequential order, orthat all illustrated operations be performed, to achieve desirableresults. Moreover, the separation of various system components in theembodiments described in this patent document should not be understoodas requiring such separation in all embodiments. Only a few embodimentsand examples are described. Other embodiments, enhancements, andvariations can be made based on what is described and illustrated inthis patent document.

What is claimed is:
 1. A substrate processing apparatus comprising: avacuum chamber; a substrate supporting unit disposed at lower portion ofan inside of the vacuum chamber; and an electric field forming unitforming an electric field inside the vacuum chamber, wherein theelectric field forming unit includes: an upper electrode disposed at anupper portion of the inside of the vacuum chamber; a lower electrodedisposed in the substrate supporting unit; and a middle electrodedisposed between the upper electrode and the lower electrode.
 2. Theapparatus of claim 1, further comprising a controller configured toapply voltages to the upper electrode, the lower electrode, and themiddle electrode.
 3. The apparatus of claim 1, further comprising a gassupplying unit including a gas distribution unit disposed in an upperportion of the inside of the vacuum chamber, wherein the upper electrodeis disposed above the gas distribution unit.
 4. The apparatus of claim1, wherein: the substrate supporting unit includes a supporting plateand an actuator configured to move the supporting plate, and the lowerelectrode is disposed in the supporting plate.
 5. The apparatus of claim1, wherein the middle electrode includes a body portion having a barshape and an end portion.
 6. The apparatus of claim 5, wherein the endportion includes an end tip having a pointed shape.
 7. The apparatus ofclaim 6, wherein the end tip includes an insulating material.
 8. Theapparatus of claim 6, wherein a point of the end tip is rounded.
 9. Theapparatus of claim 6, wherein the end portion further includes an endbody having an inclined side surface.
 10. The apparatus of claim 1,wherein the middle electrode includes: a body portion having ahorizontal bar shape, and an end portion having a bent shape.
 11. Theapparatus of claim 10, wherein the end portion includes a downwardvertex.
 12. The apparatus of claim 10, wherein the end portion has a barshape at an angle to the body portion.
 13. The apparatus of claim 1,wherein: the substrate supporting unit includes a supporting plate andan edge ring, and the middle electrode is adjacent to the edge ring. 14.The apparatus of claim 13, wherein the middle electrode penetrates theedge ring.
 15. A substrate processing apparatus comprising: a vacuumchamber; a gas supplying unit configured to supply gases into the vacuumchamber; a supporting plate disposed at a lower portion of an inside ofthe vacuum chamber; an upper electrode disposed at an upper portion ofthe inside of the vacuum chamber; a lower electrode disposed in thesupporting plate; and a middle electrode adjacent to an upper surface ofthe supporting plate, wherein the middle electrode includes an endportion configured to physically contact an edge region of a substrateon the supporting plate.
 16. A method of processing a substratecomprising: loading a wafer onto a supporting plate of a substratesupporting unit in a vacuum chamber, evacuating the vacuum chamber usinga gas exhausting unit, supplying one of a reactive gas, a precursor, ora plasma into the vacuum chamber using a gas supplying unit, andprocessing the wafer using an electric field forming unit, wherein usingthe electric field forming unit comprises forming an electric fieldincluding: applying an upper electrode voltage to an upper electrode,applying a lower electrode voltage to a lower electrode, and applying amiddle electrode voltage to a middle electrode, wherein the middleelectrode is physically in contact with the wafer.
 17. The method ofclaim 16, wherein the middle electrode voltage is a voltage between theupper electrode voltage and the lower electrode voltage.
 18. The methodof claim 17, further comprising varying the middle electrode voltagebetween the upper electrode voltage and the lower electrode voltage tocontrol physical energy directed toward the wafer.
 19. The method ofclaim 16, wherein the middle electrode voltage has a same polarity asthe upper electrode voltage.
 20. The method of claim 16, wherein themiddle electrode voltage is a ground voltage.